Keywords:

chronic fatigue syndrome;

diagnosis;

epidemiology;

myalgic encephalomyelitis;

pathophysiology;

prognosis;

review;

treatment

Background – In this article, current scientific knowledge on the chronic fatigue syndrome (CFS) is reviewed. The US case definition of CFS (the CDC-definition) is most widespread in research and clinical practice. Estimates of prevalence vary from 0.2% to above 2%. The female–male ratio is approximately 3:1.

Clinical Features – Severe fatigue is the dominating complaint; it is worsened from exertions and not substantially relieved by rest. In addition, the patients might have a varying combination of accompanying symptoms. Clinical evaluation should be based upon standardized guidelines, including an assessment of functional impairments.

Treatment – Cognitive behavioural therapy and graded exercise therapy are of proven value in randomized controlled trials. Several pharmaceutical measures have been explored and found to have no beneficial effect. Most patients might expect long-term improvement, but full recovery is rare; however, the prognosis is better among adolescents.